The present invention concerns a conductive elastomeric interface for a pin grid array.
Several methods in the prior art are available to connect a pin grid array to a printed circuit board. For example, spring connectors may be used. For example, a spring connector series of PCB connectors is available from Yokowo Co. Ltd. having a business address of No. 5-11, Takinogawa 7-Chome, Kita-ku Tokyo 114, Japan. Also, various spring contact probes are available from Everett/Charles Contact Products Inc., having a business address of 1064 Yosemite Drive, Milpitas, Calif. 95035. However, for many applications, these spring connectors can be too tall. In addition, it can be difficult to interface the spring connectors to metalized pads on printed circuit boards. Also, spring connectors are expensive and too inductive for many applications. Further, many of the spring connectors will not work on a pitch of less than 0.100 inches.
Elastomer sheets are also available for connections. See for example high density matrix connector available from Fujipoly, Inc. having a business address of 750 Walnut Ave. P.O. Box 1050, Cranford, N.J. 07016. However, for printed grid arrays of over 500 pins, such sheets may not provide a reliable contact. In addition, for printed grid arrays of over 500 pins, the force required to compress all the pins into the elastomer sheet may result in bowing in the printed circuit board.
A custom fuzz button interface also is available, for example from Cinch Connector Division of Labinal Components and Systems, Inc., having a business address of 1500 Morse Ave., Elk Grove Village, Ill. 60007. A machined phenolic material holds electrical contacts. The contacts are cylinders of bunched wire (fuzz buttons). However, pins within a pin grid array sometimes have solder tips which can snag the fuzz button wire upon extraction. Additionally, the fuzz button interfaces are expensive to manufacture and have an inductive signal path. Further, the available fuzz button interface requires a distance of 0.172 inches or greater between printed circuit boards.